Abstract

When two uncharged conducting plates are placed parallel to each other in vacuum there is an attractive force between them that is proportional to the inverse fourth power of their separation. This is the standard Casimir effect. Its existence, as well as the inverse-fourth-power dependence on the plate separation have been verified experimentally. For a wide range of plate separations this force can be seen to result entirely from the change in the electromagnetic vacuum energy brought about by the presence of the plates. (Outside this range of separations the detailed material properties of the plates must be considered, i.e., they can no longer be treated as perfect conductors.) In effect, the plates change the boundary conditions on the electromagnetic field, which alters the mode structure of the field and, hence, changes the vacuum energy. This shift in the vacuum energy between the plates relative to the vacuum energy outside the plates produces the attractive force. Green's function techniques provide a straightforward approach to computing this force.

© 1991 Optical Society of America